1. Field of the Invention
The present invention relates to a rubber composition and a fuel tank packing for an automobile using the composition, and more specifically, to a rubber composition to be used in, for example, a fuel tank packing for an automobile and a fuel tank packing for an automobile using the composition.
2. Description of the Related Art
A fuel tank packing (rubber packing) has been used between a fuel pump and a tank, which are assembled for supplying a fuel to an engine for an automobile, for sealing the fuel pump and the tank. For example, a fluororubber (FKM) material having a fluorine concentration content of about 66 wt % is often used in a fuel tank packing corresponding to a partial-credit zero emission vehicle (P-ZEV) regulation in North America. In recent years, however, the development of a fuel tank packing having a reduced fuel permeation amount has been requested in view of environmental problems, and even the use of the above-mentioned fluororubber having a fluorine concentration content of about 66 wt % cannot correspond to the requested characteristic. In view of the foregoing, for example, a fluorine-containing elastomer composition using a high-fluorine concentration content fluororubber has been proposed for solving the problem (see Japanese Patent Application Laid-open No. Hei 6-157686).